If you travel overseas a lot, you may want to get into a phone with wifi and a SIP (VoIP) client. No roaming or data charges ever when you dial via skype on your cell.
When I'm overseas, I hook into a local wifi hotspot & dial home via skype, for something like a tenth of a cent per minute, while my colleagues come home to $500 cell service bills.
An example of such a phone would be the Nokia E71. It's GSM, so you'd be with ATT or T-Mobile. Yeah, it's more expensive to buy, but pays for itself quickly if you'd otherwise rack up big service bills.
It really pays to research the various carrier modes (GSM, CDMA, etc) and put together a list of features you want in a phone, then just narrow it down.
But if your needs are simple, and you don't travel overseas, or need to sync your calendar & contact list between cell and computer, or get web service, or log into your company's email server, or use bluetooth file transfer, or navigate via the free Google Maps for Mobile, just get any piece of **** with any provider. There's a lot to be said for simplicity.
